/tests/modeltests/field_subclassing/fields.py
https://code.google.com/p/mango-py/ · Python · 76 lines · 54 code · 17 blank · 5 comment · 8 complexity · 63a6ca5c6361ad091bfaf8ffd03cb6be MD5 · raw file
- from django.core.exceptions import FieldError
- from django.db import models
- from django.utils import simplejson as json
- from django.utils.encoding import force_unicode
- import warnings
- warnings.filterwarnings("ignore", category=DeprecationWarning, module='django.db.models.fields.subclassing')
- class Small(object):
- """
- A simple class to show that non-trivial Python objects can be used as
- attributes.
- """
- def __init__(self, first, second):
- self.first, self.second = first, second
- def __unicode__(self):
- return u'%s%s' % (force_unicode(self.first), force_unicode(self.second))
- def __str__(self):
- return unicode(self).encode('utf-8')
- class SmallField(models.Field):
- """
- Turns the "Small" class into a Django field. Because of the similarities
- with normal character fields and the fact that Small.__unicode__ does
- something sensible, we don't need to implement a lot here.
- """
- __metaclass__ = models.SubfieldBase
- def __init__(self, *args, **kwargs):
- kwargs['max_length'] = 2
- super(SmallField, self).__init__(*args, **kwargs)
- def get_internal_type(self):
- return 'CharField'
- def to_python(self, value):
- if isinstance(value, Small):
- return value
- return Small(value[0], value[1])
- def get_db_prep_save(self, value):
- return unicode(value)
- def get_prep_lookup(self, lookup_type, value):
- if lookup_type == 'exact':
- return force_unicode(value)
- if lookup_type == 'in':
- return [force_unicode(v) for v in value]
- if lookup_type == 'isnull':
- return []
- raise TypeError('Invalid lookup type: %r' % lookup_type)
- class SmallerField(SmallField):
- pass
- class JSONField(models.TextField):
- __metaclass__ = models.SubfieldBase
- description = ("JSONField automatically serializes and desializes values to "
- "and from JSON.")
- def to_python(self, value):
- if not value:
- return None
- if isinstance(value, basestring):
- value = json.loads(value)
- return value
- def get_db_prep_save(self, value):
- if value is None:
- return None
- return json.dumps(value)